The value of Tonya's car is $21,000. The car's value depreciates at a rate of 15% per year.

Which function represents the value of the car after t years?

O f(t) = 1.15(21,000)

O f(t) = 21,000(1.15)

O f(t)21,000(0.85)

O f(t) = 0.85(21,000)